Resilient screw fastener



a 1952 J. w. FLETCHER, JR 2,581,238

RESILIENT SCREW FASTENER Filed May 13, 1946 JOHN W. P1 Era/2 J2 I IN V EN TOR.

Patented Jan. 1, 1952 UNITED STATES" PATENT OFFICE RESILI'ENT SCREW FASTENER John W. Pletcher, Jr., South Bend, Ind.

1 Application May 13, 194$,Serial No. 669,327 2 Claims. (01. 85-36) This invention relates to improvements in resilient screw fasteners.

The primary-object of the invention is to provide a device of this character which is simple in construction, easy to apply, and which is strong and sturdy.

A further object is to provide a device of this character which serves effectively both as a fastener and as a resiiient member to take up vibration and thereby prevent loosening or release of the fastener incident to vibration.-

A further object is to provide a device of this character which is usable with threaded members of different diameters and threads within a predetermined range so that it is not'necessary to use a device constructed specially to fit a given threaded part or screw.

Other objects will be apparent from the following description and specification.

In the drawing: 7

Fig. 1 is a view of one embodiment of the invention as seen when viewing the end of a threaded part.

Fig. 2 is a sectional view taken on line 2--2 of Fig. 1.

Fig. 3 is a perspective view of the fastener.

Fig. 4 is a sectional view similar to Fig. 2 illustrating a modified embodiment of the invention.

Fig. 5 is a sectional view similar to Fig. 2 and illustrating another type of assembly with which the device may be used.

Referring to the drawing, and particularly to Figs. 1 to 3, which illustrate one embodimentof the invention, the numeral ill designates a fastener. This fastener is formed from: sheet metal havingrequisite hardness and resilience; i. e., spring stock. The fasten'eris formed-from an elongated substantially rectangular blank of .sheet stock, and has a central fiat portion l2 defined by transverse bends M from which similar flat end portions 55 extend at acute angles in angularly diverging relation. The ends of portions l6 terminate in substantially equally spaced relation to the central portion l2 opposite the longitudinal center thereof, and are spaced apart a distance less than the diameter of the screw or threaded part IS with which the fastener cooperates and upon which it is mounted.

The fiat central portion 52 of the fastener has transversely elongated aperture 20, preferably of oval shape, formed therein in equi-spaced relation to the end-defining bends l4 and also centeredtransversely of portion l2. The dimension of aperture at itsmajor axis exceeds'the diameter of the threadedpart l8 measured at the crest inexpensive tomanufacture,

of the threads thereof; and the diameter of said aperture at its minor axis is preferably equal to the diameter of the threaded part measured at the root of the threads. The free edges of the portions It of the fasteners have shallow curved notches 22 therein centrally thereof and of a width exceeding the diameter of threaded part i 8.

The device is intended for use with a threaded member l8 having flat faces 24 at diametrically opposite portions thereof which are spaced apart a distance not greater than the thread-root diameter of member 18. The member 18 will pref erably have the usual enlarged head, 26 at one end thereof which may be of any conventional or desired shape and size and which is here shown as. a. carriage bolt head. The threaded member passes through the articles which are to be secured tog-ether thereby, for example, through the registering apertures 28 in the members 3! and 32, and is of a length to project therefrom at its threaded end.

The fastener is applied over the projecting end of the threaded member, with its part l2 innermost, by holding the same in position with the major axis of aperture 20 parallel to the fiat face '24. When so positioned, the fastener may be slid longitudinally on member 18 to a position with part 92 thereof bearing against and in engagement with the part 30. Thereupon, the parts may be interlocked by relative rotation of the fastener and threaded member approximately in a thread-tightening direction. The angle of rotation need not be exactly 90 but must be suffici-ent for interlocking of the fastener with the threads 34 between the flats. 2L and less than or such angle which would permit release of that interlocking engagement at the flats 24. It will be observed that a double interlock is provided, 'i'. e., at the part i 2 and at the ends of the parts Id. In other words, the edges of aperture 20 adjacent the minor axis thereof fit between threads 34, and the notched portions 22 fit between threads spaced longitudinally from those engaged by the edges of aperture 20. p

' By reason of the resilience of the fastener, it is placed under stress or tensioned by the advance of the parts to follow the lead of the threads upon the partial rotation. Thus tight frictional engagement of part I2 with member 3!! is achieved, together with astressed or tensioned position of parts I6. These factors cause the device to serve a function similar to a springor look washer, so that vibration of the parts is absorbed byflexingof the fastener, and there is no tendency of the fastener to rotate to releasing position incident to such vibration. To insure a tight interlock of the notched edges 22 of parts IS with the threads 34, the same may be bent for yielding frictional engagement with the flats 24 while being applied, as is obvious. This also serves to insure automatic accommodation of variations in the size or diameter of said threaded member :8.

The form of the fastener illustrated in Fig. 4 is the same as that shown in Fig. 3 with the exception that the aperture 20' in the central portion thereof is preferably circular and is of a larger diameter than the threaded member 18' so as to fit freely thereover. Consequently, the threaded member 18' may have its threads 34 extending continuously therearound and the formation of flat faces thereon is unnecessary. The edges of parts is have the same notches 22 as above described.

In the use of this form of the device, the fastener may he slid over the threaded member [8 with the portion 12 foremost without requiring any predetermined angular relation of the parts for the operation. Inasmuch as the parts [2 are in a trailing position, they are free to spring over the threads 34 during application of the fastener. When the part 12 engages part 30, the fastener and threaded member may be relatively rotated to the extent required to firmly lock the parts l2, I8, 30 and 32. This embodiment of the invention has all of the advantages of the Fig. 3 embodiment, except that of double, longitudinally spaced threaded interlocked engagement of the parts. It also possesses the advantages of adaptability for use with any threaded part or screw, relative rotation on the threaded part through any angle desired, and applicability to a wider range of sizes of threaded parts. In the latter connection, it will be apparent that the opening 20' may be quite large since no interlock is effected at part 12. Therefore, by changing the angle at which the parts 16 are bent, and therefore the spacing of the notched edges 22. the fastener may be adapted to threaded members of any size ranging from the largest size which will pass through aperture 29 down to the smallest size which the notches will accommodate without requiring the notched edges to engage each other.

While the fastener finds its greatest application in cooperation with threaded members, it has other applications also. One such application is illustrated in Fig. 5, and uses a fastener of the same type as shown in Fig. 1 and described above. In this application the outermost part 32 to which part 30 is to be secured has a stud 35 fixed thereto and projecting therefrom. The stud is plain, with the exception of a circumferential groove 38 therein spaced from the inner face of member 30. The groove 38 may be of any desired transverse shape, as the arcuate shape shown, and is preferably wider and deeper than the customary grooves between standard screw threads. For such installations the fastener is preferably designed to cooperate and fit tightly with the parts with which it is used. In other words, it is so proportioned and dimensioned that it will slide freely over the stud into engagement with part 3!], and then by a slight pressure the free ends of the parts [2 thereof will drop into and anchor themselves firmly in the groove 33 without substantial release of the applied tension. This embodiment of the device has particular utility for use in manufacturing processes where a fastener of positive action adapted to apply at least slight tension, capable of fast assembly, and which is easily manipulablc for intentional release of the assembled parts, is desired. Itjwill be apparent that the stud in this case need not be of circular cross-section, and that the groove need not extend continu ously therearound, inasmuch as any stud providing opposed grooves for receiving the free ends of parts It may be used.

Other embodiments of the fastener which fall within the spirit of the invention and the scope of the claims are deemed to be included within the purview of the invention.

I claim:

.1. In combination, a screw-threaded securing member having diametrically opposed flats, and a fastener member comprising a stiff resilient elongated body bent transversely to define a central portion and a pair of converging end portlons, said central portion having an elongated opening therein having a major dimension greater than the diameter of said securing memher and a minor dimension for interlocking engagement with said screw threads and greater than the spacing of said flats, the free edges said end portions being adapted for resilient interlocking engagement with said screw threads, said securing member being freely slidably insertible in said fastener when said flats are parallel to the major dimension of said elongated opening and interlocking with said fastener at the opening of said central portion and at the free edges of said end portions upon partial rctation of one of said securing and fastener members relative to the other.

2. In combination, a screw-threaded securing member having diametrically opposed flats. and a fastener member comprising a stiff resilient elongated body bent transversely to define a cental portion and a pair of converging end por tions, said central portion havin an elongated opening therein having a major dimension greater than the diameter of said securing memher and a minor dimension for interlocking enagement with said screw threads and greater than the spacing of said flats, the free edges oi REFERENCES CITED The following references are of record in'thc file of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,049 Tinnerman Mar. 10, 1942 1,243,859 Neider Oct. 23, 1917 1,261,014 Dorgan Apr. 2, 1918 1,472,242 Covi Oct. 30, 1923 1,890,348 Weatherhead Dec. 6, 1932 2,200,702 Oddie May 14, 1940 2,230,916 Tinnerman Feb. 4, 1,941 2,259 425 Murphy -e Oct. 14,1941 2,342,690 Place Feb. 29, 1944 2,451,223, Shippee Nov. 16, 1948 

